Tube straightening machine



Sept. l1, 1945. c. 1 DEWEY TUBE STRAIGHTENING MACHINE Filed Feb. 6, 1943 4 Sheets-Sheet l SePt- 1l 1945 c. L DEWEY 2,384,457

TUBE STRAIGHTENING MACHINE Filed Feb. 6, 1943 4 Sheets-Sheet 2 C. L. DEWEY Sept. 11, 1945.

TUBE STRAIGHTENING MACHINE Filed Feb. 6, 1943 4 Sheets-Sheet 3 Sept. 1l, 1945.

c. DEWEY 2,384,457 TUBE STRAIGHTENING MACHINE 'Filec Feb. 6. 1943 4 Sheets-Sheet 4 FTQ' 4 27, ZZ

Pnenadsept. 11,1945

UNITED sTATEs PATENT or-FicE f TUBE STBAIGHTENING MACHINE Clarence L. Dewey, Elkhart, Ind. Application February 6, 1943, Scriai No. 474,923

(cl. 15s-54) Claims.

The machine of the present invention is de-l signed primarily to straighten the walls of cylindrical tubing and remove therefrom any slight bends, kinks, or inequalities therein and to give exact and substantially-uniform circularity to the tube wall throughout. As incidental and preliminary to the tube straightening operation I havev found that it is highly desirable to subject the tube to a slight reducing operation 'in the manner hereinafter described, in order to rework the metallic structure of the tube wall suiiiciently to remove any previous set of fibers therein so that when the tube is nally straightened, there will be no tendency for the tube walls to restore to their previous condition of inequality, thereby producing a tube of increased strength due to the reworking'of the metal and one which will be The left-end axle section il of each roll carries a sprocket Il which is keyed thereto, but aside from the Presence of said sprocket, the mountings for the rolls are uniform at each end so that a description for one will suilice for both. The reduced axle section of each roll at each end is `iournaled within an adjustable journal block Il which has an adjusting stem threaded thereinto which stem is entered between hardcned spacer plates 2| and through an over-hanging flange 22 and is threaded at its outer end 23 to receive a nut 24 which permits the journal block to'be moved radially to the degree necesprovided for the mounting and driving of the combined reducing and straightening rolls and to the `general bconstruction of the machine as a whole and the constituent parts thereof.

In the drawings illustrating'the invention,

Figure 1 is a left-hand end view of a machine embodying four rolls of uniform construction arranged in radial relation'to the tube and drive from a common source of power;

Fig. 2 is a longitudinal view partly in section taken on the olf-set line 2 2 of Fig. 1;

Fig. 3 is an emerged vlongitudinal sectional view taken on line 3-3 of Fig. l; and

Fig. 4 is a cross-sectional view taken on vthe oh- The machine as a whole is mounted upon a base frame I 0 which carries a left end frame plate Il and a similarly spaced right end plate, not shown, which plates in unison provide a mounting for the opposite ends of a platform I2 which carries the rolls and associated working portions of the mechanism. The rolls i3 in the embodiment shown are four in number and are equally spaced from one another with their axes in parallel relation to the center axis of the machine which is coincident with the axis ofthe tube T to be reduced and straightened. Although the fourrolls are preferred, a greater'or lesser number may be employed, and it is not the intention to limit the invention to that number of rolls unless other- Wise indicated in the claims'. From each of the rolls extends a left-end reduced axle section Il and a similarA right end axle section I5, which sections are surrounded by thrust ball-bearings.

II and H respectively.

sary to uniformly adjust the acting surfaces of the rolls comprising the group to the required distance from the axis A and when adjusted to the desired extent permits the journal blocks to be clamped tightly against the hardened spacer plates 2| so that the hardened plates will resist the thrust of the rolls when exerting a reducing and straightening pressure upon the wall of the t tube.

The over-l-hanging flange 22 extends continu-l ously around the periphery of a rugged, integral frame 25 which, as shown in Fig. l, is of generally octagonai shape presenting flattened comers 2i which provide for the mounting of the adjusting stems 28, the rolls occupying the corner povsitions with relation to the frame 25.

Each of the journal blocks le rides within a radially extending rectangular recess 21 open toward the center which, as shown in Fig. 4, is

defined by an inwardly extending marginal flange 2l which extends continuously around the inner margins of the recesses which in unison Apresent the star-shaped configuration shown, and the marginal anges toward the outer end of each recess unite'in a widened oor section ,29 giving to this portion of the structure an arch-shaped configuration which affords clearance for the front and rear axle sections of the respective rolls.

The `1on1-nal blocks abut against the inwardly .protruding marginal i'lang 28' and kare held in The frame 25 at its base merges into a base plate I2 and at its inner edge is extended laterally to provide side wings It which receive thru bolts Il running between the front and rear frames,

which bolts are reduced and shouldered and threaded at their ends to receive nuts l! which thus serve to rigidly unite the front and rear frame sections into a unified frame supported upon the platform l2 by bolts 31.

rolls which are of truly cylindrical contour along the acting surfaces of the threads, the crests of which throughout the straightening Portions of the rolls, are flattened as at l so that each crest 6 presents a line contact, rather than a point con- The rolls Il, which more particularly form the subject matter of the present invention, are each provided with a continuous spirally extending rib or thread il, the convolutions of which at the intake end of the roll are of inwardly increasing diameter and with rounded contacting edges 39 giving to this portion of the acting surface of the roll a slightly tapered connguration which gradually reduces the clearance space between the rolls for about half the distance traversed by the tube in passing through the machine. This right-hand portion of each of the rolls may properly be termed the reducing section which imparts a slight reduction to the diameter of the tube and serves to feed the` tube forwardly by a screw action as the rolls are rotated in unison in a manner presently to be described. l

It will be noted, moreover, that the convolutions `of the spiral thread or Irib are spaced from one another by intervening gaps or valleys, so that at any given instant. each roll will contact the tube wall along a longitudinal line of separated points with intervening clearances which permit the fibers of the metal to `now'or readiust them- 80 selves during the reducing-operation and prevent excessive frictional contact which would interfere with said flow and readjustment and would tend to result in a galling or abrasion of the tube surface which is avoided by imparting the compressive stresses at separatedpoints in the manner stated. It will, of course, be understood that as the tube advances, and is subjected to rotation. each point of contact will become a constituent of a spirally extending continuous line which is the resultant of the application of the radially directed pressure against the surface of a rotating and constantly advancing tubewall and which will tendto impart a slight spiral grooving to the tube surface which, however, is flattened down or largely obliterated by reason of the fact that the convolutions in the respective rolls are stepped or staggered so that they will not track or follow in the same line with one another.

Thus, as seen in Fig. 3, the crests of the upper4 6l convolutions stand opposite the gaps or valleys of the lower convolutions while the intermediate rolls will respectively measure oi! one-fourth and three-fourths of the distance so that the four advancement of the tube itself, due to the forward feeding action of the screw threads. will in a large measure. if not entirely, break up any continuity in the formation of' spiral grooves i.

the surface of the tube. Atl the sametime the spacing of the points of, contact, with the' provision of intermediate gaps, as the tube is forced progressively througlfa contracting clearance space, will in unison rework and compact the iibers of the metal in such a way as to work out. and obliterate any inequalities in the diameter of the tube and newly displace and compress tact with the tube surface, which contact lines as the tube is rotated will become the constituents of relatively broad spiral bands or stripes as distinguished from the spiral lines which are the l" resultant of the contacts provided by the rounded convolutions in the reducing portions of the rollI structure. Since the roll surfaces throughout the straightening sections of the rolls maintain an equal spacing throughout from the axis of the l5 tube, and since the convolutions of the respective rolls are stepped or staggered in the manner previously mentioned, it is evident that during the passage of the tube through the straightening section of the machine, any remaining inequalities in the 'surface will be smoothed down or -ironed out so that the tube when delivered will 'present a smooth, even,'and truly cylindrical surface from end to end.

Suitable means are provided for uniformly driv- 425 ing all of the rolls from a single source of power.

and mechanism for performing this result is shown in detail in Fig. 1 although it will be understood that other equivalent means may be employed for obtaining this result.

As shown, all of the sprockets il are encircled by an endless sprocket chain 4I which embraces each of the sprockets in sumcient degree to engage several of the sprocket teeth; and in order to maintain such engagement, the opposite'turns ofthe sprocket chains are carried inside of simirolls, acting in unison, in conjunction with thethe fibers so that when the tube emerges from the machine. it will not only be of truly circular section but will be toughened and hardened to a substantial degree.

Although the reducing ends ofthe rollsproduce the result above specined, itis desirable to vadditionally straighten andiron out the surface by, passing it through the terminal sections of the it section of the mounting Il, the stemterminating larly spaced idler sprockets l2 carried by stub shafts 4l below which the'sprocket chain is carried around a centrally disposed driving sprocket Il keyed upon a horizontal transmission shaft U carrying a worm gear It which meshes, with a 'worm 41 on a worm shaft 4l, which in turn carries a pulley 49 driven by a belt Il carried around pulley Il on a motor shaft l2 which is driven by a motor Il mounted upon' a'slide U4 adjustably frame il permitting foreqand-aft adjustment.

In order to provide for the taking up or releasing of slack in the sprocket chain. due to the radial adjustment of the rolls to accommodate tubing of different diameters, the driving sprocket and parts carried thereby areverticaliy able as indicated in Figs. 1 and 2; v

To provide for such adjustment the shaft 4lis surrounded by bushings Il and a which are carried bya Journal mounting I1 comprising forward and rear sections Il and Il which are' recessed on their inner faces Il and Il respectively to provide a chamber for the worm'gear and the worm 41. The-two sections are united by bolts Il. and the bushing Ils is socketed within arecess Il inanextension fromthesection Il.' which arrangement provides an extended Journai for the shaft Il. The Journal mounting is provided on each side with fins il which travel within guide slots ll 'and ,over-lying lplates O1 Y secured by bolts lltotheforwardframe plate Il, which uns are lof sumcient length to afford an extended slide mounting to prevent cramping or binding under 'the preponderance of weight on the rear side of the forward frame plate.4 v

Vertical adjustment is aifordedby a screw Il which is provided at its-upper end with'a smooth stemllpassingthroughalug'ilonthefoxward supported upon a plate Il carried by the base in a reduced and threaded extension 12, carrying a nut I3 which coacts with a hexagonal flat-faced portion 1l on the lower side of the lug in affording a journal mounting for the screw which per-v mits a wrench to be applied to the fiat-faced collar to rotate the screw. The lower end of the screw is threaded into a post shouldered and bolted to the forward edge of thenbase frame Ill immediately in advance of an arched opening I6 in the forward frame plate which affords clearance for the vertical movements of the journal mounting and for the location of the screwand associated parts.

In order to take up or release slack in the motor belt ill, occasioned by the vertical adjustments of the journal mounting 51, an adjustmentk screw 1l is provided, the forward end of which is journaled within an angle-shaped bracket 18 carried by the floor plate 55, and the rear threaded end of which is entered through a lug 19 on the base l"plate 54 of the motor which affords limited longitudinal adjustment to the motor as occasion may require.

Variable speeds may be imparted to the motor through the provision of an adjustable switch il!)I of any suitable character.

Operation Although the present method requires a preliminary slight reduction in the tube diameter, this reducing operation is performed primarily for the purpose of reworking the metal fibers to eliminate inequalities and to strengthen and toughen the metaLand the reducing is therefore to be regarded as preliminary to the straightening operation, and as incidental thereto and in most, if not all', cases the reduction will proceed by with particularity as to detail, it is not intended,

unless otherwise indicated in the claims, to limit the construction to the number of rolls shown or t0 the herein described method of mounting and driving the rolls, since modifications in these details may be made without departingfrom the spirit of the invention.

Although in the embodiment shown the forward feeding of the tube' is occasioned by the screw-feeding action on the tube which will be rotated bythe bite of -the rolls as its advancement begins. 'I'he gradual progressive increase in the diameter of the convolutions will correspondingly decrease the clearance space so that as the tube section advances, it will be gradually reduced in sufficient amount to rework the metallic fibers of lthe tube wall, thereby eliminating the previous set of the fibers and working,v out any inequalities in the circularity of the tube.

At the same time the method of applying the reducing pressures at equal distances on different sides of the tube and in radially opposed directions to one another will accurately center the tube so that its axis will exactly coincide with the axis of the clearance space. The spacing of the convolutions serves to apply the reducing pressures at any' instant along aligned points extending longitudinally of the tube surface so that the reducing stresses at any instant will be applied to minute areas of the tube surface rather than along continuous lines of contact, 'thereby affording opportunity for a redistribution of the metal fibers as the reducing operation progresses. While a single convoluted reducing roll might cause the formation of spiral grooves in the tube surface, the provision of a group 0f rolls, preferably not less than three innumber, and with the convolutions progressively staggered, will substantially smooth out and obliterate any perceptible grooving so that as the tube passes through the flat-edged terminal convolutions, its surface will be ironed out andv subjected throughout a. considerable extent to a uniform. smoothing operation which gives to` the tube the final smoothing and centering effect required.

screw action of the convlute ribs without the employment of additional feeding force, `it is to be understood that on occasion itmay be desirable to supplement the screw feeding action by the employment of any suitable means of a character well understood in the art.

I claim: 1

' l. The method of straightening tubing which consists in applying reducing pressures with blunt edged ribs against different faces of the tube wall and directed inwardly radially toward the axis of the tubing, said pressures being applied at any instant in slightly converging lines of separated points, said points moving longitudinally of the tube wall and being the constituents of rotating and spirally moving continuous lines of reducing pressure contact, progressively and in equal degree approaching the axis of the tubing while undergoing relative rotation and relative linear advancement, and by progressive reduction, rework-l ing the metal fibers' of the tubing, and after such` reduction subjecting the tube wall to straightening pressures .with ribs fiat in transverse crosssection directed inwardly radially toward different faces of the tube wall and being applied at any given instant inl parallel lines of separated contacts equally 4spaced throughout from the axis of the tubing, and being the constituents of rotating and spirally moving planes of straightening pressure contact and serving to subject the tube wall to a smoothing and straightening operation.

2. The method of straightening tubing which consists in applying reducing pressures with blunt edged ribs against different faces of the tube wall and directed inwardly radially toward the axis of the tubing, said pressures being applied at any instant in slightly converging lines of separated points, .said points advancing longitudinally of the tube wall and being the constituents of not less than three rotating and spirally advancing continuous'` non-tracking lines of reducing pressure contact, progressively and in equal degree approaching the axis of the tubing while undergoing relative rotation and relative linear advancement, and by progressive reduction, reworking the metal flbers of the tubing, and after such reduction subjecting the tube wall to straightening pressures with ribs flat in transverse cross-sec-4 tion directed inwardly radially toward different.

faces ofthe tube wall and being applied at any given instant in parallel lines of separated contacts equally spaced throughout from th axis of A the tubing, andbeing the constituents of not less than three rotating land spirally advancing planes of straightening pressure contact and serving to subject the tube wall toa smoothing` and straightening operation, the separated straightening contacts being longitudinally extended as line pres- .preaching the axis of the tubing while undergoing relative rotation and relative linear advancement, and by progressive reduction, reworking the tinuations of the rotating and spirally advancing lines of reducing pressure contact.

4. I'he method of straightening tubing which consists in applying reducing pressures with blunt edged ribs against different faces of the tube wall and directed inwardly radially toward the axis of the tubing, said pressures being applied at any instant in not less than three slightly converging lines of separated points, said points advancing longitudinally of the tube wall and being the constituents of rotating and spirally advancing nontracking continuous lines of reducing pressure contact, progressively and in equal degree approaching the axis of the tubing while undergoing relative rotation and relative linear advancement, and by progressive reduction, reworking the metal fibers of the tubing, and after such reduction subjecting the tube wall to straightening pressures with ribs flat in transverse cross-section directed inwardly radially toward not less than three different faces of the tube wall and being applied at any given instant in parallel lines of separated contacts substantially equally spaced throughout from the axis of the tubing, and beingthe constituents of rotating and spirally advancing nontracking continuous planes of straightening pressure contact and serving to subject the tube wall to a smoothing and straightening operation, the.

metal fibers of the tubing, and after such reducv tion subjecting the tube wall to straightening pressures with ribs natin transverse cross-section d'rected inwardly radially towarddlfferent' faces of the tube wall and being applied at any given instant in not less than three parallel lines'A of separated contacts equally spaced throughout from the axis of the tubing, and being the constituents of rotating and spirally advancing nontracking continuous planes of straightening pressure contact and serving to subject the tube wall to a smoothing vand straightening operation, the

rotating and spirally advancing lines of straightening pressure contact being uninterrupted conseparated straightening contacts being longitudinally extended as line pressures to span, at any given instant a substantial extent of the tube surface, the rotating and spirally advancing lines of straightening pressure contact being uninterrupted continuations of the rotating and spirally 85 advancing lines of reducing presslu'e contact.

5. Apparatus for straightening tubing including a roll having a generally helical blunt-edged rib of gradually increasing diameter to effect a slight degree of reduction, the terminal portions 40 of said rib means4 being flat-faced in cross-section ai smoothing operation after the tube has been slightly reduced.

CLARENCE L. DEWEY.

continuous uniform diameter to effect a l 

